  //1 4 5 8 2 3 9 10
  //left 1 4 5 8 8 8 9 10
  //right     10  10 10 10 

  //height 1,0,2,1,0,1,3,2,1,2,1
  //left   1,1,2,2,2,2,3,3,3,3,3
  //right  3,3,3,3,3,3,3,2,2,2,1 

  let arr = [1,2,3,4]
  let arr2 = arr.pop()
  console.log(arr);
  console.log(arr2);
  
  